irclog2html for #brlcad on 20051129

00:39.13 pra5ad sean
03:02.34 *** join/#brlcad ibot (i=ibot@pdpc/supporter/active/TimRiker/bot/apt)
03:02.34 *** topic/#brlcad is http://brlcad.org/ || BRL-CAD is now Free Software! || 7.6.4 is released || Developer meeting on Friday Nov 17!
03:19.17 *** join/#brlcad Twingy (n=justin@pcp0011649600pcs.aberdn01.md.comcast.net)
03:57.22 *** join/#brlcad fenn (n=4462aa53@bz.bzflag.bz)
05:28.36 *** join/#brlcad DTRemenak|RDP (n=DTRemena@DHCP-170-143.caltech.edu)
05:40.18 *** join/#brlcad autoeagle (n=9fe23f82@bz.bzflag.bz)
05:43.46 autoeagle hi,is any body here?
05:44.27 *** join/#brlcad autoeagle (n=9fe23f82@bz.bzflag.bz)
05:44.45 brlcad hello
05:45.09 brlcad someone's always here, we're just not always quick to respond ;)
05:47.33 autoeagle But I can't find any one or any information in the channel.
05:49.20 autoeagle I have a question about the usage of the Brlcad.
05:52.55 autoeagle If there are an existent function or software in the brlcad that could determine a point in or out of the model which build by brlcad?
05:54.19 autoeagle If not, i want try to develop one for my project.
05:55.36 autoeagle Beside, how to use the irc?
05:57.49 learner determine a point in or out of the model?
05:58.03 learner like shooting a ray and determining the entry and exit hit point?
05:58.11 learner that's exactly what brl-cad is designed around ;)
05:59.33 brlcad there are various net ettiquite rules for irc, the most important is probably to just be patient and ask well thought out questions if you have questions
06:00.13 brlcad the conversation comes and goes so you pretty much stay in the channel while you do other things and check it from time to time
06:01.23 brlcad as for your question about determining the in and out points of an intersection, it also matters whether you mean in the modeler or in code (both of which are possible
06:02.06 brlcad in mged, you can run nirt or shoot_ray to fire a single ray (default is from the view center) and it will report some default hit information
06:02.38 brlcad in code, rt_shootray() is where it all happens, and you register callbacks that get called on a hit/miss at which point you can report in/out points, etc
06:03.04 brlcad e.g. look at src/rt/rtexample.c in the source distribution for a simple example that reports in and out hit points
06:03.14 autoeagle In fact,it is not a very effective way to determine by shooting a ray and determining the entry and exit hit point.
06:03.50 brlcad not effective for what purpose?
06:04.23 brlcad and again, are you talking about code or user tools in brl-cad or just theoretically?
06:05.35 learner most who use irc don't use that web interface, there are binary apps available for most all platforms (http://irchelp.org is a decent starting point)
06:06.14 autoeagle In my project , the in or out test must be done more than billions times for a model.
06:07.51 autoeagle In some case , such as the solid base on mesh, the ray test is effective for in and out test.
06:07.57 brlcad billions isn't too bad, that's on par with the analysis simulations that are written to use brl-cad
06:08.48 brlcad brl-cad csg ray-tracer can handle several million rays per second on a decent machine
06:09.31 brlcad and if that's not fast enough, there is a triangle/mesh-based ray-tracer that can handle considerably more in brl-cad
06:09.38 autoeagle And my model base on about 140 solid.
06:09.50 brlcad that's a tiny model :)
06:10.45 brlcad most of the models we're used to dealing with have thousands
06:10.55 brlcad or tens of thousands
06:11.03 autoeagle I think so.
06:13.29 brlcad so it sounds then that you're interested in the programmatic interfaces in brl-cad?
06:14.55 autoeagle but my project include 1M particles. each one need the in or out test per turn.And the whole process includes more than 100,000 turn,
06:16.32 brlcad that should be pretty straight-forward to implement
06:16.51 brlcad though if it's a particle system you're implementing, you probably don't need full-blown ray-tracing
06:17.19 brlcad you just need simple locale-specific collision detection and velocity updates
06:17.35 brlcad that would be a cool feature to add to brl-cad
06:17.53 autoeagle Yes
06:17.55 brlcad there's minimal particle system and time-based update support
06:19.03 brlcad that said, you certainly 'could' implement the particle system using the ray-tracer pretty darn easily
06:20.15 autoeagle theoretically, a simple locale-specific collision could save 50-90% calculate time vs ray test.
06:20.28 Maloeran Adding code to break out of adrt's tracing loop after travelling a certain distance wouldn't be much trouble, for local collision tests
06:20.36 brlcad you'd shoot a ray for every particle, every timestep to determine if/where they intersect -- it would take about 1s per timestep on a desktop
06:21.08 brlcad that'd be about a 26 hour computation on a desktop
06:21.16 brlcad for 100k timesteps
06:21.38 autoeagle really?
06:21.39 brlcad you can undoubtedly improve upon that given the simple nature of the sim
06:23.32 brlcad the main killer time sink by ray-tracing is probably going to be prep time since the model changes every time step, i'd bet that'd account for most of the time without some customization
06:25.28 autoeagle Yes,In my project , the rebuild of the list will cost about 90% calculations.
06:26.26 brlcad what are your time constraints? what's the goal? an animation of the simulation? a (real-time?) simulation framework?
06:27.45 autoeagle not real time.
06:28.09 brlcad no sense worrying about whether it's going to take 26 hours or 40 hours if real-time is a requirement; vice-versa if real-time isn't a requirement and you're just rendering off-line, no bid deal if it simulates and renders for a day
06:30.36 autoeagle but the now effection is too bad.So i want to optimize it with brlcad.
06:31.25 autoeagle the first step the change the modeling system to mged
06:31.45 brlcad if you represent your particles with spheres or triangles, you should get optimal raytrace performance using rt or adrt respectively
06:31.50 autoeagle the first step is to change the modeling system to mged
06:32.06 brlcad please do :)
06:36.59 brlcad in the meanwhile, presuming you're going to hang around (which I hope you do) -- I'd suggest http://www.irssi.org/ or http://www.xchat.org/ for an irc client
06:37.28 autoeagle thank you:)
06:40.22 autoeagle which Networks should I choice in Xchat.
06:42.06 CIA-12 BRL-CAD: 03brlcad * 10brlcad/NEWS: it's 7.6.5, not 7.6.6 quite yet..
06:42.08 brlcad irc.freenode.net
06:42.23 brlcad #brlcad
06:43.28 brlcad (port 6667)
06:43.34 CIA-12 BRL-CAD: 03brlcad * 10brlcad/TODO: fix perf.sh pathing issue
06:43.40 brlcad fg
06:45.22 CIA-12 BRL-CAD: 03brlcad * 10brlcad/TODO: test pic/nonpic build problems with librtms/libmultispectral
06:48.42 brlcad welp, time for me to sleep a lil bit I think
06:48.55 brlcad nice talking to you autoeagle, see you around more hopefully
06:50.36 autoeagle thank you.
06:51.21 autoeagle bye
06:52.32 autoeagle blushing for my poor english.
07:05.54 *** join/#brlcad cad954 (n=9fe23f82@bz.bzflag.bz)
07:06.12 *** join/#brlcad autoeagle (n=9fe23f82@bz.bzflag.bz)
07:07.16 *** join/#brlcad cad694 (n=9fe23f82@bz.bzflag.bz)
07:12.45 *** join/#brlcad cad575 (n=9fe23f82@bz.bzflag.bz)
08:13.56 *** join/#brlcad DTRemenak|RDP (n=DTRemena@DHCP-170-143.caltech.edu)
09:24.35 *** join/#brlcad learner (n=brlcad@pcp0011649376pcs.aberdn01.md.comcast.net)
09:24.35 *** mode/#brlcad [+o learner] by ChanServ
12:21.45 *** join/#brlcad brlcad_ (n=brlcad@bz.bzflag.bz)
12:30.00 *** join/#brlcad archivist (n=archivis@host217-35-76-52.in-addr.btopenworld.com)
13:51.07 *** mode/#brlcad [+o brlcad] by ChanServ
15:49.37 *** join/#brlcad Maloeran (n=alexis@modemcable084.164-81-70.mc.videotron.ca)
18:58.58 *** join/#brlcad cad009 (n=0c0b8913@bz.bzflag.bz)
19:03.04 *** join/#brlcad DTRemenak (n=DTRemena@DHCP-170-143.caltech.edu)
19:10.04 *** join/#brlcad DTRemenak (n=DTRemena@DHCP-170-143.caltech.edu)
20:59.36 *** join/#brlcad raz (n=raz@pool-138-88-142-43.esr.east.verizon.net)
21:01.47 raz twingy: we are running the isst apps but not seeing anything rendered. we followed the usage steps in the readme. Any input?
21:12.06 ``Erik is it printing the framerate in the console?
21:27.49 raz the splash screen shows up and the caption reads: ADRT_ISST_Observer Loading...
21:37.43 ``Erik hrm, lemme go kick justin and make him look at irc o.O
21:39.47 raz thanks

Generated by irclog2html.pl by Jeff Waugh - find it at freshmeat.net! Modified by Tim Riker to work with blootbot logs, split per channel, etc.